Context-aware systems can dynamically adapt to user situations to provide smarter services. In general, context refers to the information that can be used to characterize these situations, and context models are deployed to specify contextual information described in context-aware systems. However, even though user context is highly dynamic, existing context models either focus on modeling static views of context or lack appropriate design abstractions to deal with dynamic aspects and interactions involving contextual elements such location, time, user roles, social relationships, and changing preferences. Moreover, virtual environments have not been modelled by most of the existing context models even though online interaction is very common and popular. This thesis presents a dynamic user-centric context model that can be used to model the aspects of context-aware systems that are subject to frequent change. Four case studies are proposed to illustrate the applicability of the approach taken by this thesis, and they are in the domains of mobile e-healthcare, mobile commerce, mobile tourism, and mobile augmented reality gaming. Benefits of the proposed model include avoiding the development of context-aware systems from scratch, enabling future use of model-driven approaches, and reducing implementation effort.

This thesis develops a generalized approach for decoupling how a context model is defined and executed from how context-aware data is acquired and managed within a given middleware system. Decoupling the model specification from the data will likely provide more avenues of context-aware investigations due to an increased flexibility in the choice of a middleware system for handling context data. We provide a detailed description of the approach developed for this decoupling task, called Inspect, Adapt, Model, and Integrate (IAMI). By engaging the steps we show that a context model need not be specifically tied to a given context-aware middleware. This successful decoupling will likely add to the future development of context-aware systems by allowing researchers to build upon existing frameworks as opposed to repeatedly engaging in ground-up development. Moreover, we submit that this decoupling is important in that the number of possible ways of representing and expressing a context model is potentially infinite, but the choice of context-aware middleware systems is limited.

Magister Scientiae - MSc / Stress responsive genes play a key role in shaping the manner in which plants process and respond to environmental stress. Their gene products are linked to DNA transcription and its consequent translation into a response product. However, whilst these genes play a significant role in manufacturing responses to stressful stimuli, transcription factors coordinate access to these genes, specifically by accessing a gene's promoter region which houses transcription factor binding sites. Here transcriptional elements play a key role in mediating responses to environmental stress where each transcription factor binding site may constitute a potential response to a stress signal. Arabidopsis thaliana, a model organism, can be used to identify the mechanism of how transcription factors shape a plant's survival in a stressful environment. Whilst there are numerous plant stress research groups, globally there is a shortage of publicly available stress responsive gene databases. In addition a number of previous databases such as the Generation Challenge Programme's comparative plant stressresponsive gene catalogue, Stresslink and DRASTIC have become defunct whilst others have stagnated. There is currently a single Arabidopsis thaliana stress response database called STIFDB which was launched in 2008 and only covers abiotic stresses as handled by major abiotic stress responsive transcription factor families. Its data was sourced from microarray expression databases, contains numerous omissions as well as numerous erroneous entries and has not been updated since its inception.The Dragon Arabidopsis Stress Transcription Factor database (DASTF) was developed in response to the current lack of stress response gene resources. A total of 2333 entries were downloaded from SWISSPROT, manually curated and imported into DASTF. The entries represent 424 transcription factor families. Each entry has a corresponding SWISSPROT, ENTREZ GENBANK and TAIR accession number. The 5' untranslated regions (UTR) of 417 families were scanned against TRANSFAC's binding site catalogue to identify binding sites. The relational database consists of two tables, namely a transcription factor table and a transcription factor family table called DASTF_TF and TF_Family respectively. Using a two-tier client-server architecture, a webserver was built with PHP, APACHE and MYSQL and the data was loaded into these tables with a PYTHON script. The DASTF database contains 60 entries which correspond to biotic stress and 167 correspond to abiotic stress while 2106 respond to biotic and/or abiotic stress. Users can search the database using text, family, chromosome and stress type search options. Online tools have been integrated into the DASTF, database, such as HMMER, CLUSTALW, BLAST and HYDROCALCULATOR. User's can upload sequences to identify which transcription factor family their sequences belong to by using HMMER. The website can be accessed at http://apps.sanbi.ac.za/dastf/ and two updates per year are envisaged. / South Africa

In this thesis we investigate several methods how to improve the quality of statistical machine translation (MT) by using linguistically rich information. First, we describe SemPOS, a metric that uses shallow semantic representation of sentences to evaluate the translation quality. We show that even though this metric has high correlation with human assessment of translation quality it is not directly suitable for system parameter optimization. Second, we extend the log-linear model used in statistical MT by additional source-context model that helps to better distinguish among possible translation options and select the most promising translation for a given context.

The latest developments of mobile devices include a variety of hardware features that allow for more rich data collection and services. Numerous sensors, Internet connectivity, low energy Bluetooth connectivity to other devices (e.g., smart watches, activity tracker, health data monitoring devices) are just some examples of hardware that helps to provide additional information that can be beneficially used for many application domains. Among others, they could be utilized in mobile learning scenarios (for data collection in science education, field trips), in mobile health scenarios (for health data collection and monitoring the health state of patients, changes in health conditions and/or detection of emergency situations), and in personalized recommender systems. This information captures the current context situation of the user that could help to make mobile applications more personalized and deliver a better user experience. Moreover, the context related information collected by the mobile device and the different applications can be enriched by using additional external information sources (e.g., Web Service APIs), which help to describe the user’s context situation in more details. The main challenge in context modeling is the lack of generalization at the core of the model, as most of the existing context models depend on particular application domains or scenarios. We tackle this challenge by conceptualizing and designing a rich generic context model. In this thesis, we present the state of the art of recent approaches used for context modeling and introduce a rich context model as an approach for modeling context in a domain-independent way. Additionally, we investigate whether context information can enhance existing mobile applications by making them sensible to the user’s current situation. We demonstrate the reusability and flexibility of the rich context model in a several case studies. The main contributions of this thesis are: (1) an overview of recent, existing research in context modeling for different application domains; (2) a theoretical foundation of the proposed approach for modeling context in a domain-independent way; (3) several case studies in different mobile application domains.

Vývoj v informačním systému neustále zvyšuje nároky na účinnou, efektivní a adaptivní spolupráci mezi komponenty systému, aby se vyrovnal se změnami v systému a zaručil tak nejlepší výkon. K dosažení těchto požadavků byly zavedeny dva hlavní přístupy. Přístup k adaptaci umožňuje informačnímu systému přizpůsobit se změnám v kontextu informací systému a jeho okolního prostředí na základě adaptační strategie. Přístup ke zvyšování informovanosti zase napomáhá sledovat informace o kontextu a rozpoznat změny, které mohou proces adaptace vyvolat. V této práci představujeme obecný kontextově orientovaný model vlastní adaptivní architektury pro podporu softwarového systému s adaptačními funkcemi, které zaručují dostupnost systému, provozní podmínky a výkon. Navíc poskytujeme dvě případové studie v reálném životě jako důkaz konceptu použitelnosti našeho navrhovaného adaptačního přístupu.

Die "Kontextsensitivität" genannte systematische Berücksichtigung von Umweltinformationen durch Anwendungssysteme kann als Querschnittsfunktion im betrieblichen Umfeld in vielen Bereichen einen Nutzen stiften. Wirklich praxistaugliche kontextsensitive Anwendungssysteme, die sich analog zu einem mitdenkenden menschlichen Assistenten harmonisch in die ablaufenden Vorgänge in der Realwelt einbringen, haben einen enormen Bedarf nach umfassenden, d.h. diverse Aspekte der Realwelt beschreibenden Kontextinformationen, die jedoch prinzipbedingt verteilt in verschiedenen Datenquellen, etwa Kontexterfassungssystemen, Endgeräten sowie prinzipiell auch in beliebigen anderen, z.T. bereits existierenden Anwendungen entstehen. Ziel dieser Arbeit ist die Verringerung der Komplexität des Beschaffungsvorganges von verteilten und heterogenen Kontextinformationen durch Bereitstellung einer einfach verwendbaren Methode zur Darstellung eines umfassenden, aus verteilten und heterogenen Datenquellen zusammengetragenen Kontextmodells. Im Besonderen werden durch diese Arbeit zwei Probleme addressiert, zum einen daß ein Konsument von umfassenden Kontextinformationen mehrere Datenquellen sowohl kennen und zugreifen können und zum anderen über die zwischen den einzelnen Kontextinformationen in verschiedenen Datenquellen existierenden, zunächst nicht modellierten semantischen Verbindungen Bescheid wissen muß. Das dazu entwickelte Kontextinformationsintegrations- und -darstellungsverfahren kombiniert daher ein die Beschaffung und Integration von Kontextinformationen aus diversen Datenquellen modellierendes Informationsintegrationsmodell mit einem Kontextdarstellungsmodell, welches die abzubildende Realweltdomäne basierend auf ontologischen Informationen durch in problemspezifischer Weise erweiterte Verfahren des Semantic Web in einer möglichst intuitiven, wiederverwendbaren und modularen Weise modelliert. Nach einer fundierten Anforderungsanalyse des entwickelten Prinzips wird dessen Verwendung und Nutzen basierend auf der Skizzierung der wichtigsten allgemeinen Verwendungsmöglichkeiten von Kontextinformationen im betrieblichen Umfeld anhand eines komplexen betrieblichen Anwendungsszenarios demonstriert. Dieses beinhaltet ein Nutzerprofil, das von diversen Anwendungen, u.a. einem kontextsensitiven KFZ-Navigationssystem, einer Restaurantsuchanwendung sowie einem Touristenführer verwendet wird. Probleme hinsichtlich des Datenschutzes, der Integration in existierende Umgebungen und Abläufe sowie der Skalierbarkeit und Leistungsfähigkeit des Verfahrens werden ebenfalls diskutiert. / Context-awareness, which is the systematic consideration of information from the environment of applications, can provide significant benefits in the area of business and technology. To be really useful, i.e. harmonically support real-world processes as human assistants do it, practical applications need a comprehensive and detailed contextual information base that describes all relevant aspects of the real world. As a matter of principle, comprehensive contextual information arises in many places and data sources, e.g. in context-aware infrastructures as well as in "normal" applications, which may have knowledge about the context based on their functionality to support a certain process in the real world. This thesis facilitates the use of contextual information by reducing the complexity of the procurement process of distributed and heterogenous contextual information. Particularly, it addresses the two problems that a consumer of comprehensive contextual information needs to be aware of and able to access several different data sources and must know how to combine the contextual information taken from different and isolated data sources into a meaningful representation of the context. Especially the latter information cannot be modelled using the current state of the art. These problems are addressed by the development of an integration and representation model for contextual information that allows to compose comprehensive context models using information inside distributed and heterogeneous data sources. This model combines an information integration model for distributed and heterogenous information (which consists of an access model for heterogeneous data sources, an integration model and an information relation model) with a representation model for context that formalizes the representation of the respective real world domain, i.e. of the real world objects and their semantic relations in an intuitive, reusable and modular way based on ontologies. The resulting model consists of five layers that represent different aspects of the information integration solution. The achievement of the objectives is rated based on a requirement analysis of the problem domain. The technical feasibility and usefulness of the model is demonstrated by the implementation of an engine to support the approach as well as a complex application scenario consisting of a user profile that integrates information from several data sources and a couple of context-aware applications, e.g. a context-aware navigation system, a restaurant finder application as well as an enhanced tourist guide that use the user profile. Problems regarding security and social effects, the integration of this solution into existing environments and infrastructures as well as technical issues like the scalability and performance of this model are discussed too.

[pt] A construção de sistemas hipermídia/multimídia requer a implementação de um elemento responsável por receber a especificação de um hiperdocumento (sua estrutura, seus relacionamentos e a descrição da forma de exibição desejada) e concretizá-la na apresentação propriamente dita, sendo esse módulo de controle de execução comumente denominado formatador hipermídia. O objetivo desta tese é discutir os aspectos referentes ao projeto e desenvolvimento de formatadores hipermídia, propondo um modelo de execução de hiperdocumentos e uma estrutura genérica (framework) capaz de ser reutilizada na implementação de sistemas hipermídia. Em particular, o trabalho aborda as questões referentes à adaptação dos documentos antes e durante as suas apresentações, às estratégias de antecipação das ações de exibição (mecanismos de pré-busca), aos mecanismos de integração com os exibidores de mídia e aos mecanismos de integração com a infra-estrutura de exibição (em especial, sistema operacional e rede). A proposta apresentada segue uma especificação orientada a objetos, definindo uma arquitetura para sincronização temporal e espacial na exibição de hiperdocumentos, que pode ser utilizada também em outros domínios de aplicação que necessitem de sincronização em tempo real. / [en] The development of hypermedia/multimedia systems requires the implementation of an element responsible for receiving the specification of a hyperdocument (structure, relations and presentation descriptions) and controlling the presentation. This execution control module is commonly known as hypermedia formatter. The goal of this thesis is to discuss the aspects related to the design and implementation of hypermedia formatters, proposing a hyperdocument execution model and a framework to be reused in the implementation of hypermedia systems. In particular, this work deals with document adaptation issues, both before document presentation and on-the-fly, prefetching mechanisms, integration with presentation tools, and integration with the infrastructure (in special, operating system and network). The proposal presented follows an object-oriented specification approach, defining an architecture for temporal and spatial synchronization in hyperdocument presentations. The proposal can also be used in other application domains that need real-time synchronization.

Un intérêt accru a été élevé sur les systèmes d'apprentissage mobiles contextualisé. Ces systèmes visent à fournir les supports d'apprentissage via des appareils mobiles et de les adapter aux besoins spécifiques de l'éducation, les caractéristiques personnelles et les circonstances particulières d'un apprenant ou un groupe d'apprenants interconnectés. L'apprentissage en milieu de travail est une approche essentielle pour promouvoir l'efficacité de travail et d'apprentissage des professionnels. Il est besoin ciblé, personnalisé, juste-à-temps et basé sur la localisation. Ces caractéristiques prédisent que le système d'apprentissage mobile contextualisé peut jouer un rôle dans la promotion de l'efficacité de l'apprentissage en milieu de travail. Cependant, il y a relativement peu de systèmes d'apprentissage mobiles contextualisé proposées pour le développement de l'apprentissage et de la compétence en situation de travail. Cet article propose la conception, la mise en œuvre et l'évaluation d’un système d'apprentissage mobile contextualisé pour le milieu professionnel, nommé WoBaLearn. Plus précisément, dans la thèse, nous avons travailler sur: (1) les théories de l'apprentissage mobile contextualisé et l'apprentissage en milieu de travail; (2) les approches pour la conception d'un système d'apprentissage mobile contextualisé pour le milieu professionnel; et (3) les technologies et les méthodologies de mettre en œuvre et de tester le système d'apprentissage conçu. Les principales contributions de cette thèse sont: 1) Construction d’un modèle de contexte hiérarchique et basé sur une ontologie pour l'apprentissage en milieu de travail Nous avons défini un modèle de contexte initial pour décrire l'information contextuelle de l'apprentissage mobile en milieu de travail, nommé WbML. Ce modèle adopte l'approche hiérarchique, et est construit par l'ontologie. 2) Proposition d’un ensemble de stratégies d'adaptation pour l'apprentissage en milieu de travail et un moteur d'apprentissage pour exécuter ces stratégies Nous avons proposé un ensemble de stratégies d'adaptation. Ces stratégies adapter les supports d'apprentissage en fonction du contexte d’apprentissage actuel. Nous avons proposé également un moteur d'adaptation qui exécute ces stratégies pour mettre en œuvre les adaptations d'apprentissage. 3) Conception de l’architecture d’un système d'apprentissage mobile contextualisé pour le milieu professionnel Combinant avec les bases conceptuelles sur le modèle de contexte, des contenus d'apprentissage, les stratégies d'adaptation et le moteur d'adaptation, nous avons proposé l'architecture de WoBaLearn système qui permet à WoBaLearn de réaliser des services d'apprentissage adaptatif. 4) Mise en œuvre du système et son évaluation avec une étude de cas Nous avons implémenté le système avec les technologies modernes, et mis une étude de cas pour évaluer ce système. Les résultats d'évaluation nous ont fourni la preuve que ce système peut offrir aux professionnels une expérience d'apprentissage satisfaisant et faciliter leurs activités de travail. / Increased interest has been shown in context-aware mobile learning systems. These systems aim to provide learning supports via mobile devices and adapt them to specific educational needs, personal characteristics and particular circumstances of an individual learner or a group of interconnected learners. Work-based learning is a crucial approach to promote professionals’ working and learning efficiency, which is need-targeted, personalized, just-in-time and location-based. These characteristics predict that context-aware mobile learning systems can play a role in promoting the effect of work-based learning. However, relatively few context-aware mobile learning systems are proposed for learning and competence development in work contexts. This dissertation proposes the design, implementation and evaluation of a context-aware mobile system for work-based learning, named WoBaLearn. More specifically, in the dissertation, we worked on: (1) the learning theories related to work-based context-aware mobile learning; (2) the approaches for designing a work-based context-aware mobile learning system; and (3) the technologies and methodologies for implementing and testing the designed system. The main contributions of this thesis are: 1) Proposal of an ontology-based hierarchical context model for work-based learning We defined an initial context model for describing contextual information in work-based mobile learning, named WbML. This model adopts a hierarchical designing approach which classifies con-text into a common layer and a domain layer. This approach improves the reusability of this context model. Also, the WbML context model is built based on ontology for describing context semantically. 2) Design of a set of adaptation strategies for work-based learning and an adaptation engine to execute these strategies We proposed a set of adaptation strategies concerning learning units selection, learning units sequence, learning units navigation, learning partners communication, and learning activities generation. These strategies adapt learning supports depending on professionals’ just-in-time learning con-text. We proposed also an adaptation engine which executes these proposed strategies to implement learning adaptations. 3) Construction of the WoBaLearn architecture Combined with the conceptual design bases about the context model, learning contents, adaptation strategies and adaptation engine, we proposed the system architecture of WoBaLearn which enables the WoBaLearn system to achieve the adaptive learning services. 4) Implementation of WoBaLearn We implemented the proposed system with modern technologies, and set a user study to evaluate it. Evaluation results provided us with the evidence that this system can offer professionals a satisfactory learning experience and facilitate their work activities.

<p>Stress responsive genes play a key role in shaping the manner in which plants process and respond to environmental stress. Their gene products are linked to DNA transcription and its consequent translation into a response product. However, whilst these genes play a significant role in manufacturing responses to stressful stimuli, transcription factors coordinate access to these genes, specifically by accessing a gene&rsquo / s promoter region which houses transcription factor binding sites. Here transcriptional elements play a key role in mediating responses to environmental stress where each transcription factor binding site may constitute a potential response to a stress signal. Arabidopsis thaliana, a model organism, can be used to identify the mechanism of how transcription factors shape a plant&rsquo / s survival in a stressful environment. Whilst there are numerous plant stress research groups, globally there is a shortage of publicly available stress responsive gene databases. In addition a number of previous databases such as the Generation Challenge Programme&rsquo / s comparative plant stressresponsive gene catalogue, Stresslink and DRASTIC have become defunct whilst others have stagnated. There is currently a single Arabidopsis thaliana stress response database called STIFDB which was launched in 2008 and only covers abiotic stresses as handled by major abiotic stress responsive transcription factor families. Its data was sourced from microarray expression databases, contains numerous omissions as well as numerous erroneous entries and has not been updated since its inception.The Dragon Arabidopsis Stress Transcription Factor database (DASTF) was developed in response to the current lack of stress response gene resources. A total of 2333 entries were downloaded from SWISSPROT, manually curated and imported into DASTF. The entries represent 424 transcription factor families. Each entry has a corresponding SWISSPROT, ENTREZ GENBANK and TAIR accession number. The 5&rsquo / untranslated regions (UTR) of 417 families were scanned against TRANSFAC&rsquo / s binding site catalogue to identify binding sites. The relational database consists of two tables, namely a transcription factor table and a transcription factor family table called DASTF_TF and TF_Family respectively. Using a two-tier client-server architecture, a webserver was built with PHP, APACHE and MYSQL and the data was loaded into these tables with a PYTHON script. The DASTF database contains 60 entries which correspond to biotic stress and 167 correspond to abiotic stress while 2106 respond to biotic and/or abiotic stress. Users can search the database using text, family, chromosome and stress type search options. Online tools have been integrated into the DASTF&nbsp / database, such as HMMER, CLUSTALW, BLAST and HYDROCALCULATOR. User&rsquo / s can upload sequences to identify which transcription factor family their sequences belong to by using HMMER. The website can be accessed at http://apps.sanbi.ac.za/dastf/ and two updates per year are envisaged.</p>